Explosives at forefront of airport security measures.

THE TRANSPORTATION SECURITY Agency modified its list of prohibited items in carry-on luggage in December. This marked a shift from the post-9/11 focus of preventing terrorists from taking over airplanes to thwarting would-be bombers.

"I am convinced that the time now spent searching passengers' bags for small scissors and tools does not add to our security. These are not the tools of the terrorists. We must focus our attention on the far more dangerous threat of explosives," said the Transportation Security Administration assistant secretary Kip Hawley.

The popularity of improvised explosive devices as a weapon of choice for terrorists has prompted the TSA to continue installing screening machines that can detect explosives.

Darrin Kayser, TSA spokesman, said 59 explosives trace portal machines have been installed at 24 airport security checkpoints across the country.

Slightly larger than the walk-through metal detectors, these portals require passengers to step inside one at a time and stand still for a few seconds as puffs of air blow particulates off their clothes from head to foot. Within a matter of seconds, the machine analyzes any microscopic particles knocked loose for traces of explosives. If none are found, a computerized voice will tell passengers to exit the portal. But if it discovers any positive results, the machine will immediately alert screeners.

Kayser said the agency is in the process of purchasing 103 additional machines.

To further fortify security, said Hawley, the agency plans to increase the number of canine explosives detection teams, currently at 360.

Not only will passengers be closely scrutinized for traces of explosives but their checked bag gage also will undergo more stringent screening. Lockheed Martin Corp. is testing an advanced certified explosives detection system at Sky Harbor International Airport in Phoenix, Ariz. and John Wayne Airport in Orange County, Calif.

Using computed tomography-screening technology, the upgraded EDS system produces a three-dimensional, color image of the contents of a bag as it moves through an automated screening area.

In President Bush's 2007 budget, the TSA requested $4.7 billion for aviation security. The Office of Management and Budget reports that the agency "will commit more than $690 million to purchase, install and maintain baggage screening devices, including in-line systems that will increase baggage throughput up to 250 percent." In addition, $80 million will fund emerging technologies at passenger checkpoints.